A request is made for a high sensitivity cryoprobe to increase the sensitivity and throughput of an existing modern 600 MHz NMR system. This system is currently heavily used for biomolecular NMR studies by three major users: Dr. Chien Ho: Biophysical and Molecular Biological Studies on Hemoglobin. Dr. Miguel Llinas: NMR Studies of Plasminogen and Related Genomic Domains. Dr. Gordon Rule: Structure and Dynamics of Glutathione transferases. The requested cryoprobe will also support the research efforts of Dr. Pei Tang (minor user) in her research efforts directed at investigating the molecular basis of anesthetic action. In summary, the cryoprobe/cryoplatform will increase the sensitivity and throughput of the instrument. The increase in sensitivity will allow the research groups to perform experiments that are currently not practical on our existing instruments. In addition, the increase in sensitivity will dramatically increase the throughput of the instrument. This increase in efficiency will allow the NIH supported research projects to progress towards their goals in an accelerated fashion. In addition, it will be possible for the participating investigators to explore additional experimental systems and/or approaches that were not possible due to the constraints imposed by limitations in instrument time and sensitivity. Finally, the increased throughput of the system will allow the facility to accommodate a larger number of occasional users who have a need for high-field instrumentation.